AIR PUMP NOISE BEAT OR MOAN REPLACEMENT INFORMATION

Some 1983 Certurys with 3.0L V6 engines and eleven (11) cubic inch A.I.R. pumps, may exhibit a "beat" or moaning type noise on hard, or moderate acceleratior. It may also be noticeable at steady highway speeds. If loosening or removing the A.I.R. pump belt eliminates or reduces the noise, take the following action to correct:

Replace the A.I.R. pump pulley and belt with part numbers as listed below:

A.I.R. Pump Pulley Part No. 25510368

A.I.R. Pump Belt With Vacuum Pump 9433838 Without Vacuum Pump 9433832

NOTICE: Engines equipped with 19 cubic inch A.I.R. pumps (late 1983 production) should not exhibit this condition and must not receive this repair.

PUMP IDENTIFICATION INFORMATION

Pump Size Pump Size

11 cu. in. 19 cu. in.

Width 4" 5 1/8"

End Plate Cast Aluminum Cast Iron (Black)

Broadcast Code MM BX

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.